A layer selection module for a graphics display component, and method therefor. The layer selection module is arranged to identify a set M of active layers to be blended for a pixel, configure a display controller to generate composite pixel data for the pixel based on a subset N of up to n layers from the set M, determine whether a number m of active layers in the set M exceeds n, and output an indication of which active layers within the set M were excluded from the subset N, if it is determined that the number m of layers in the set M exceeds n.